Julia Jekyll and Harriet Hyde

Julia Jekyll and Harriet Hyde was a sitcom on CBBC in the mid to late 90s about a schoolgirl called 'Julia Jekyll' (who had a best friend at the fictional school called the 'Rocket Academy' by the name of 'Edward');

Her monstrous alter ego was 'Harriet Hyde' and she always had to keep this a dark secret from anyone other than herself.